6 Meters

1
6 Meters

• The Mystery Band
• by Marc C. Tarplee, Ph.D.
• N4UFP

2
6 Meters Rhetoric vs. Reality

• No one is on 6 meters
• (Ive made over 1500 QSOs on 6 m since 1992)
• There is no DX on 6 meters
• (Ive worked 46 states and 38 countries on 3
  continents)
• 6 meters is the TVI band
• (I have never had a TVI complaint from my
  neighbors)

3
What makes 6 m interesting?

• A wide variety of operating modes is available
• No band offers a wider range of propagation
  phenomena than 6 m
• Station equipment requirements are modest
• Antenna experimentation is much easier on 6 m
  than the HF bands

4
6 Meter Band Plan

• 50.0-50.1 CW, beacons (beacon sub band
  50.060-50.080 MHz)
• 50.1-50.3 SSB, CW (SSB calling frequency
  50.125 MHz)
• 50.10-50.125 DX window
• 50.3-50.6 All modes
• 50.6-50.8 Nonvoice communications (digital
  calling frequency 50.62 MHz)
• 50.8-51.0 Radio remote control (20-kHz channels)
• 51.0-51.1 Pacific DX window
• 51.12-51.48 Repeater inputs (19 channels,
  digital repeater inputs are 51.12-51.18 MHz)
• 51.62-51.98 Repeater outputs (19 channels,
  digital repeater outputs are 51.62-51.68 MHz)
• 52.0-52.48 Repeater inputs (except as noted 23
  channels)
• 52.02, 52.04 FM simplex
• 52.2 TEST PAIR (input)
• 52.5-52.98 Repeater output (except as noted 23
  channels)
• 52.525 Primary FM simplex
• 52.54 Secondary FM simplex
• 52.7 TEST PAIR (output)
• 53.0-53.48 Repeater inputs (except as noted 19
  channels)
• 53.0 Remote base FM simplex
• 53.02 Simplex

5
6 Meter Propagation

• Every type of propagation is possible on 6 m
• Line of Sight
• Tropospheric Propagation
• Sporadic E
• Meteor Scatter
• Auroral Scattering
• Transequatorial F
• Ionospheric F2

6
Line of Sight (LOS) and Tropospheric Propagation

• Line of Sight
• LOS coverage is determined primarily by the
  height of the transmitting and receiving antennas
• For typical amateur 6 m stations LOS coverage is
  about 20 miles
• LOS propagation is unaffected by solar
  conditions, time of day or the seasons
• Tropospheric Propagation
• Variations in the humidity of the troposphere
  cause RF to be scattered over the horizon. This
  is known as tropospheric scatter
• Temperature inversions (warm dry air located
  above cool moist air) refract RF in the VHF range
  back towards the earth. Temperature inversions
  occur daily in the middle latitudes at sunrise
  and sunset. Communications are possible over a
  ranges up to 600 miles
• Over the oceans, stable temperature inversions
  can create a duct, through which VHF can travel
  without significant loss up to 2500 miles

7
Tropospheric Scatter
Tropospheric Ducting
8
Sporadic E (ES)

• Clouds of high density ionization form without
  warning in the ionospheres E layer
• ES is not dependent on solar activity. It may
  occur any time, but is most frequent between May
  and August, with a smaller peak of activity in
  December
• Single hop ES has a range of 1400 mi
• Double hop ES has a range of 2500 mi
• Cause of Sporadic E is not known high altitude
  wind shear may be responsible.

9
Sporadic E (ES)

• The ionized clouds that cause sporadic E
  propagation can move. This animated sequence
  shows grid squares contacted in ½ hour intervals
  during an ES opening beginning at 2200 Z, 12 June
  1994

10
Meteor Scatter

• As meteors are vaporized in the upper atmosphere,
  they leave behind ionized trails at heights of 60
  70 miles that are sufficiently dense to reflect
  VHF
• A long trail lasts only 15 seconds so contact
  must be made quickly on SSB
• SSB QSOs via meteor scatter are usually possible
  only during a meteor storm
• Short trails that occur continuously may be used
  for high speed CW QSOs (gt 100 wpm)
• Best time for meteor scatter is after midnight or
  during a meteor storm

11
Aurora (Au)

• During periods of intense auroral activity,
  charged particles in the auroral zone can scatter
  50 MHz RF
• The RF interacts strongly with the aurora,
  resulting in significant distortion of the
  signal. Only narrow band modes such as CW are
  used during Au openings
• To work Au, the transmitter and receiver point
  their antennas at the auroral zone, not each
  other.

12
Transequatorial F (TE)

• The ionospheres F layer is most intense in the
  region of the geomagnetic equator.
• Stations within about 2500 miles of the
  geomagnetic equator can launch 50 MHz RF into
  these regions. The RF is refracted and travels
  across the equator and into the other hemisphere
  without scattering from the ground
• Stations using TE must be at approximately equal
  distances from the geomagnetic equator

13
F2 propagation

• Communications over long distances (gt 2000 miles)
  are possible on 6 m via the F2 layer of the
  ionosphere during periods of high solar activity
  (solar flux above 220)
• Openings generally occur in spring and fall
  during daylight hours (similar to 10 m)

14
Propagation Example
2001 June VHF QSO Party 6 m QSOs
15
6 Meter Station Requirements

• Transceiver or Transverter
• RF output of at least 10 W PEP with multi-mode
  capability (CW/SSB/FM)
• ICOM 706, 746, 756
• Yaesu FT-100, 817, 847, 920
• Kenwood TS-570
• Alinco DX-70TH
• Antenna
• Gain of at least 5 dBd
• Should be rotatable
• Should be at least 20 ft above ground
• Use low loss coax (RG8 up to 75 ft, Belden 9913
  for longer runs)
• Useful accessories
• RF pre-amp (RF switched)
• Grid Square Map

16
6 Meter Antennas

• 6 m antennas are relatively small, light and
  easily rotatable.
• Best choices for a new operator
• 2 element quad
• 3 element Yagi
• Extended Double Zepp
• 6/10 dual band dipole
• For weak signal work (CW/SSB) the antenna should
  be horizontally polarized
• For repeater operation, vertical polarization is
  the norm

17
6 Meter Quad and Yagi Antennas

• 2 element Quad (square loops of 14 ins. wire Z
  60 ohms Gain 4 dBd)
• Element Loop Length (in) Position (in)
• Reflector 245.0 0
• Driver 235.5 29
• 3 element Yagi (Aluminum tubing Z 42 ohms gain
  5 dBd)
• Element Half Length (in) (0.75 dia 0.625
  dia) Position (in)
• Reflector 24 35.875 0
• Driver 24 31.875 50
• Director 24 26.375 87
• 5 element Yagi (Aluminum tubing Feed Z 35 ohms
  Gain 8 dBd)
• Element Half Length (in) (0.75 dia 0.625
  dia) Position (in)
• Reflector 24 35.875 0
• Driver 24 33.875 49
• Director 1 24 30.000 72
• Director 2 24 29.500 121
• Director 3 24 28.000 169

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Other 6 Meter Antennas

• Dipole
• Length 114 inches (14 wire) Z 70 ohms Gain
  0 dBd
• Extended Double Zepp
• Length 282 inches (14 wire) Z 45 ohms Gain
  4 dbd
• Antenna is fed at the center through a 39.25 inch
  length of 450 ohm ladder line (VF 0.9)
• 6/10 dual band dipole
• Length 198 inches (14 wire) Z 64 ohms Gain
  1 dBd
• Antenna is fed at the center through 32 feet 4
  inches of 450 ohm ladder line (VF 0.9)
• Antenna also can be used on 10 meters (Z 72
  ohms)

19
6 Meter Activities

• Contests
• ARRL January VHF Sweepstakes (3rd weekend in
  January)
• ARRL June VHF QSO Party (2nd weekend in June)
• SMIRK QSO Party (3rd weekend in June
• CQ WW VHF Contest (2nd weekend in July)
• Six Club 6 m Sprint (3rd weekend in July)
• ARRL September QSO Party (2nd weekend in
  September)
• Operating Awards
• VUCC contacts with 100 Grid Squares, not
  difficult
• WAS tough, but not impossible
• DXCC very tough from North America, but it has
  been done
• Grid Square Hunting
• There are over 500 grid squares in the
  continental US
• No one has worked them all yet (except perhaps
  for W5FF)

20
What is a Grid Square?

• Almost all VHF operating awards and contests
  involve grid squares
• Grid Squares are 2º longitude x 1º latitude
  sections of the earths surface (there are 32,400
  in total)
• Each grid square has a 4 character designator
  containing 2 letters and 2 numbers.
• The two letters designate the field. There are
  324 fields lettered AA through RR
• Each field is divided into 100 squares numbered
  00 through 99
• The continental US includes grid squares in
  fields CM,CN, DL, DM, DN, EL,EM,EN, FM and FN
• Most of Rock Hill is in grid square EM94.

21
World Grid Fields
22
Grid Square Map of the USA